A code assigned to a student upon entering an educational institution, and used to identify the student in official documents.

plural of Liouville number

(number theory) An irrational number x with the property that, for every positive integer n, there exist integers p and q with q > 1 and such that 0<|x-p/q|<1/(qⁿ).

plural of Sierpinski number

(number theory) An odd natural number k such that k⨯2ⁿ+1 is composite for all natural numbers n.

(UK politics, colloquial) Synonym of 11 Downing Street

(UK politics, colloquial) Synonym of 11 Downing Street

plural of hyperperfect number

(mathematics, number theory) Any natural number n for which, for some positive integer k, n = 1 + k(σ(n) - n - 1), where σ(n) is the sum of the positive divisors of n.

A squarefree integer with at least three prime factors which fall into the pattern p_x=ap_x-1+b, where a and b are some integer constants and x is the index number of each prime factor in the factorization, sorted from lowest to highest.